
precision lowp float;

varying vec2 vUv;
varying float vElevation;
uniform sampler2D uTexture;

void main(){
    //gl_FragColor = vec4( vUv , 0.0 , 1.0 );

    float deep = vElevation + 0.09 * 10.0 ;
    // gl_FragColor = vec4( 1.0 * deep, 0.0 , 0.0 , 1.0 );

    // 根据 uv 采样贴图
    vec4 color = texture2D( uTexture, vUv );
    color.rgb *= deep;
    // 输出颜色
    gl_FragColor = color;
}